Just try to envision the scene: A newly elected Republican mayor of a large American city takes steps to close down some of the best schools serving an almost exclusively minority population. You know how it would go. We'd be hearing that Republicans "hate" the poor. The words "cruel," "vicious" and "racist" would circle the new mayor like sharks. News organizations would examine where the mayor sent his own children, and his hypocrisy would be fiercely denounced.

It is, of course, the new Democratic mayor of New York, Bill de Blasio, who is shutting down a number of highly successful public charter schools. (His son attends a magnet school.) Charters are public schools run by parents or others and are not constrained by the usual public school rules, hours or curricula. Charters currently educate about 20 percent of the students in Harlem and the Bronx, boroughs known for a) poverty, b) unemployment and c) abysmal public schools.

Students are chosen for charter schools by lottery, and if you've seen "Waiting for 'Superman'" or "The Cartel," you've seen the excruciating drama. The Success Academy in Harlem is typical. It received 2,665 applications for 125 spots last year, making it more selective than the Ivy League. When the results are announced, a lucky few are jubilant. The faces of the remainder of the children are tear-stained and devastated. Those tears are haunting -- unworthy of a great nation. We cannot wish away the problems of centuries (the legacy of slavery and discrimination) nor quickly solve the problems of crime and family disintegration that blight the lives of so many inner-city kids. But we can give them a shot at a good education -- the indispensible (if not completely sufficient) ticket to success.

Even the very liberal New Yorker magazine acknowledges the remarkable results achieved by the Success Academy. "Last year, 64 percent of Harlem's third-graders passed the state English exam and 88 percent passed the state math exam. At P.S. 123 ... which is located in the same school building ... only 18 percent of students passed the English test and only 5 percent passed the math test."

Not every charter posts such dramatic results, and there are a few whose students don't perform as well as those in comparable public schools, but most charters outperform public schools. They feature longer school days, higher standards, more parental involvement (some schools require parents to sign a contract promising to read to their kindergarteners, first- and second-graders one hour a day) and an atmosphere of safety and respect. Many of the 53,000 New York students currently on waiting lists for charters just want a safe and quiet atmosphere for learning. As Marcus Winters of the University of Colorado has found, far from harming the public schools, the presence of a charter school tends to improve the performance of neighboring public schools. Competition works its magic.

De Blasio bulldozed into office swearing to take aim at the privileged and defend the powerless. If you know anything about leftists, you won't be surprised that he is actually training his fire on the poorest and most vulnerable. Remember that one of President Barack Obama's first acts was to attack the school choice program in the District of Columbia. De Blasio is calling for a moratorium on placements of charter schools within public school buildings (many are co-located) and proposes that charter schools be required to pay rent. He has also unilaterally revoked a promise of space made by his predecessor to three new charters associated with the Success Academy in Harlem, leaving 700 students out in the cold. Autumn Elvy, an 8-year-old charter student, told the New York Daily News that she had a message for the mayor: "Stop being mean to charter schools because it's not fair."

De Blasio, like many in his party, is a loyal servant of the teachers unions. But Gov. Andrew Cuomo has chosen to side with the parents. While de Blasio appeared last week before an assembled crowd of about 1,000 union members in matching T-shirts, Cuomo spoke at a competing rally of 7,000 or so parents.

That Democrats are beginning to fight over this question is encouraging. Republicans who haven't focused on it, perhaps thinking it doesn't affect their voters, very few of whom live in cities. That's shortsighted. This is a moral issue. No one in public life should avoid it. Besides, it betrays the cold brutality of some Democrats who claim to speak for the poor.